Global Warming Global Climate Change
Global Climate Change About 600-700 million years ago, the entire Earth may have been encased in ice It has been proposed that the top mile of the oceans may have been frozen solid
Global Climate Change About 55 million years ago, the Earth may have been completely ice free No Ice, not even at the north and south poles, nor on high mountains
Global Climate Change Global warming is the increase in the average temperature of the Earth's atmosphere and oceans since the mid-twentieth century and its projected continuation
Global Climate Change The instrumental record of global average temperatures as compiled by the of the University of East Anglia’s Climatic Research Unit in the United Kingdom since 1850 This data shows that over the past 100 years, the average surface temperature for the entire Earth, has risen almost 1 degree Celsius
Opps Global Warming Scandal Makes Scientific Progress More Difficult, Experts Say [Fox News 12/01/2009] Scientists at the University of East Anglia’s Climate Research Unit in the United Kingdom confessed to throwing out most of the raw temperature data on which the theory of global warming is founded. The loss of the data prevents other scientists from checking it to determine whether, in fact, there has been a long-term rise in global temperatures during the past century and a half.
Test Question 29. Over the past 100 years, the average surface temperature for the entire Earth?
Global Climate Change This plot is based on the NASA GISS Surface Temperature Analysis, which combines the 2001 GISS land station analysis data set with the Rayner/Reynolds oceanic sea surface temperature data set Note that while there has been an overall increase in mean temperature, there are regional and global variations
Global Climate Change There is a tremendous amount of research data that supports the hypothesis that there has been a global increase in the mean temperature over the past century, but... What caused this increase? Is it a natural cycle in the weather? Or human caused global warming?
Global Climate Change There are three main factors that directly influence the energy balance of the earth and it's temperature: Solar energy influx, which depends on the earth's distance from the sun and on solar activity Chemical composition of the atmosphere Albedo, the ability of the earth's surface to reflect light
Greenhouse Effect The greenhouse effect is the process in which the emission of infrared radiation by the atmosphere warms a planet's surface The Earth's average surface temperature of 14°C (57°F) would otherwise be about -19°C (-2.2°F) in the absence of the greenhouse effect
Test Question 31. The greenhouse effect is the process in which?
Greenhouse Gases Greenhouse gases are the gases present in the atmosphere which reduce the loss of heat into space and therefore contribute to global temperatures through the greenhouse effect Most greenhouse gases have both natural and anthropogenic (human) sources
Greenhouse Gases Before the industrial revolution, concentrations of most atmospheric gases were roughly constant Since the industrial revolution, concentrations of some gases have increased, and the evidence strongly points to this increase being due to human actions
Greenhouse Gases Three of the major greenhouse gases in the Earth’s atmosphere are: Water vapor (H20), which causes about 36–70% of the greenhouse effect on Earth (note clouds are not made of water vapor and they affect climate in a different way) Carbon dioxide (CO2), which causes 9–26% Methane (CH4), which causes 4–9%
Test Question 40. The three major greenhouse gases are?
Greenhouse Gases Other greenhouse gases include, but are not limited to: Nitrous oxide Sulfur hexafluoride Hydrofluorocarbons Perfluorocarbons Chlorofluorocarbons Ozone
Greenhouse Gases The major atmospheric constituents (nitrogen, N2 and oxygen, O2) are not greenhouse gases This is because homonuclear diatomic molecules, such as N2 and O2, do not absorb or emit infrared radiation
Greenhouse Gases – Water Vapor Under normal atmospheric conditions, water vapor is continuously generated by evaporation and removed by condensation Distribution of water vapor In the atmosphere as detected by NASA satellites
Greenhouse Gases – Water Vapor Air temperature is the primary factor that determines the percent of water vapor in the atmosphere Human activity has very little effect on the amount of water vapor
Greenhouse Gases – CO2 Carbon dioxide is the greenhouse gas that has received the most interest
Greenhouse Gases – CO2 Carbon dioxide in the Earth's atmosphere is considered a trace gas, currently occurring at an average concentration of about 385 parts per million (or 0.0385%) by volume It is generated by three major processes: Respiration Out gassing Combustion
Greenhouse Gases – CO2 Carbon dioxide is an end product in organisms that obtain energy from breaking down sugars, fats and amino acids with oxygen as part of their metabolism, in a process known as cellular respiration This includes all plants, animals, many fungi and some bacteria In higher animals, the carbon dioxide travels in the blood from the body's tissues to the lungs where it is exhaled In plants using photosynthesis, carbon dioxide is absorbed from the atmosphere
Greenhouse Gases – CO2 Up to 40% of the out gassing emitted by some volcanoes during sub aerial (underwater) volcanic eruptions is carbon dioxide According to the best estimates, volcanoes out gas about 145-255 million tons of CO2 into the atmosphere each year (Remember there are over one million undersea volcanoes)
Greenhouse Gases – CO2 Carbon dioxide is also produced as a byproduct of the combustion of fossil fuels or vegetable matter Human activity is the overwhelming source of CO2 generated from combustion Industrial Slash and burn farming
Test Question 39. The overwhelming source of CO2 generated from combustion is?
Greenhouse Gases – CO2 Since the start of the Industrial Revolution, about 150 years ago, there has been a very significant increase in carbon emissions from human activity Most of this increase has occurred in the past 50 years, with no end in sight
Greenhouse Gases – CO2 The amount of CO2 in the atmosphere has increased by 35% since 1850 and 19% since 1960 Most of this increase has occurred in the past 50 years, with no end in sight
Test Question 38. The amount of CO2 (carbon dioxide) in the atmosphere has?
Greenhouse Gases – CO2 Scientists who undertook the first comprehensive look at ocean’s storage of carbon dioxide found that the world's oceans serve as a massive sink that traps the greenhouse gas
Greenhouse Gases – CO2 It was also discovered that around half of all carbon dioxide produced by humans since the industrial revolution has dissolved into the world's oceans or about 120 billion metric tons (265 trillion pounds) Today, there is about 50 times as much carbon dissolved in the oceans as exists in the atmosphere
Test Question 28. It was discovered that around half of all carbon dioxide produced by humans since the industrial revolution has?
Greenhouse Gases – CO2 The problem is that chemically bonded carbon in the oceans has lowered the average pH of seawater by 0.1 unit, to 8.2 Predicted emissions could lower it by a further 0.5 by 2100, to a level not seen for millions of years
Greenhouse Gases – CO2 This pH change may be slowing growth of plankton, corals, and other invertebrates that serve as the most basic level of the ocean food chain Long-term impact on marine life could be severe
Greenhouse Gases – CO2 CO2 is also increasing in the thermosphere, an upper layer of the atmosphere that ranges from 55 to 370 miles (90 to 600 kilometers) above the surface and is where the atmosphere ends and space begins
Greenhouse Gases – CO2 The thermosphere interacts strongly with the sun and hence is greatly influenced by the sun's solar activity, which occurs in 11 year cycles When solar activity is high, ultraviolet radiation warms and expands the thermosphere and when activity is low, the thermosphere contracts and cools During the recent solar minimum (2007-2009), the increased CO2 cooled the thermosphere and caused it to contract far more than scientist expected
Venus, the Greenhouse Planet As seen through telescopes on Earth, Venus is shrouded in thick clouds impenetrable to visible light It was a planet of mystery
Venus, the Greenhouse Planet Venus is essentially the same size as Earth and obviously has an atmosphere It was called “Earth’s sister” Science fiction writers populated the planet with flying aliens and great oceans and other fanciful things Many scientists thought the planet might harbor life
Venus, the Greenhouse Planet Spacecraft proved they were all wrong A series of pictures of the surface of Venus were taken by four different U.S.S.R. Venera spacecraft between 1975-1982 The surface of Venus was revealed to be lifeless and desolate
Venus, the Greenhouse Planet Worse, the thick, opaque atmosphere of Venus has created an environment akin to hell Clouds are revealed when Venus is photographed in the ultraviolet by orbiting spacecraft
Venus, the Greenhouse Planet The atmosphere of Venus suffered an extremely different fate than compared to Earth because of a runaway greenhouse effect
Venus, the Greenhouse Planet The atmosphere of Venus is over 200 kilometers thick It is composed of 96.5% carbon dioxide (CO2) with clouds of sulfuric acid The average surface temperature is 460oC (860oF) The atmospheric pressure on the surface of Venus is 92 times that of the Earth There is no water on Venus
Venus, the Greenhouse Planet The water on Venus has disappeared due to the extreme temperatures brought on by the runaway greenhouse effect Water vapor rose to high elevations and was broken down into oxygen and hydrogen by ultraviolet radiation Hydrogen, being light, escaped from Venus into outer space Oxygen combined with other atmospheric gases, for example, making CO2 Therefore, the water on Venus was lost forever
Venus, the Greenhouse Planet On Earth, CO2 is constantly being absorbed into the oceans and rocks If this absorbed CO2 were completely released into the atmosphere, 98% of the Earth’s atmosphere would be composed of CO2 and the atmospheric pressure would be 70 times what it is now Earth would be a lifeless planet, just like Venus
Test Question 30. The atmosphere of Venus suffered an extremely different fate than compared to Earth because of?
Greenhouse Gases - Methane Methane is created by various abiotic processes and is released by volcanic gases It is the major component of natural gas, about 87% by volume About 3.5 billion years ago, there was 1,000 times as much methane in the Earth’s atmosphere as there is now Methane is a potent greenhouse gas